smc

168

part of the condensin complex, chromosomal origin condensation and segregation SMC protein

Locus: BSU_15940

Molecular weight: 135.29 kDa

Isoelectric point: 5.27

Protein length: 1186 aa

Gene length: 3561 bp

Function: segregation of replication origins

Product: chromosome condensation and segregation SMC protein

Essential: yes

Synonyms: smc, ylqA

Genomic Context

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List of homologs in different organisms, belongs to COG1196 (Galperin et al., 2021)

Gene

Coordinates: 1,666,560  1,670,120

Phenotypes of a mutant

• essential PubMed
• terminal phenotype of a CRISPRi knockdown mutant is moderate lysis PubMed
• ''smc'' mutants are not viable on complex medim that allow rapid growth, but they are viable under conditions of slow growth PubMed
• ''smc lethality on complex medim can be suppressed by inactivation of tmcAL and tsaC'' (constitutive stringent response) PubMed

The protein

Catalyzed reaction/ biological activity

• ATPase activity, cycles of ATP hydrolysis are used by the condensin complex to extrude DNA loops PubMed

Protein family

• SMC family (with SbcC, according to UniProt)

Domains

• SMC hinge domain (aa 519-637) (according to UniProt)

Structure

• 3ZGX (PDB) (complex between the head domain of Smc (aa 1 - 219 and 983 - 1186) and the N-terminal winged-helix domain of ScpA) PubMed
• P51834 (AlphaFold)

Effectors of protein activity

• ATP-induced DNA-binding results in a more open conformation of the Smc dimer, and thus of the condensin complex PubMed

Localization

• Nucleoid (heterogeneous) PubMed
• The condensin (Smc)₂-ScpA-ScpB complex is loaded by ParB to parS centromeric sites adjacent to the replication origin, travels then from the origin to the terminus at rates >50 kb per minute PubMed,PubMed,PubMed

Expression and Regulation

Operons

• Genes: rnc-smc-ftsY

  Description: PubMed

  Regulation

  • expressed during vegetative growth and during sporulation in the mother cell (SigK, GerE) PubMed

  Regulatory mechanism

  • stringent response: negative regulation, in stringent response

  Sigma factors

  • SigA: sigma factor, PubMed, in sigA regulon

Biological materials

Mutant

• MGNA-B148 (smc::erm), available at the NBRP B. subtilis, Japan
• 1A822 ( smc::pMUTIN trpC2 Em), PubMed, available at the Bacillus Genetic Stock Center
• BEC15940 (smc::erm  trpC2), a CRISPRi knockdown mutant, PubMed, is available at the Bacillus Genetic Stock Center

References

Reviews

Gogou C, Japaridze A, Dekker CMechanisms for Chromosome Segregation in Bacteria.Frontiers in microbiology. 2021; 12:685687. PMID: 34220773
Gruber S SMC complexes sweeping through the chromosome: going with the flow and against the tide. Current opinion in microbiology. 2018 Apr; 42:96-103. pii:S1369-5274(17)30149-2. doi:10.1016/j.mib.2017.10.004. PMID:29182912
Uhlmann F SMC complexes: from DNA to chromosomes. Nature reviews. Molecular cell biology. 2016 Jul; 17(7):399-412. doi:10.1038/nrm.2016.30. PMID:27075410
Hajduk IV, Rodrigues CD, Harry EJ Connecting the dots of the bacterial cell cycle: Coordinating chromosome replication and segregation with cell division. Seminars in cell & developmental biology. 2016 May; 53:2-9. doi:10.1016/j.semcdb.2015.11.012. pii:S1084-9521(15)30010-0. PMID:26706151
Gruber S Multilayer chromosome organization through DNA bending, bridging and extrusion. Current opinion in microbiology. 2014 Dec; 22:102-10. doi:10.1016/j.mib.2014.09.018. PMID:25460803
Nolivos S, Sherratt D The bacterial chromosome: architecture and action of bacterial SMC and SMC-like complexes. FEMS microbiology reviews. 2014 May; 38(3):380-92. doi:10.1111/1574-6976.12045. PMID:24118085
Reyes-Lamothe R, Nicolas E, Sherratt DJ Chromosome replication and segregation in bacteria. Annual review of genetics. 2012; 46:121-43. doi:10.1146/annurev-genet-110711-155421. PMID:22934648
Lenhart JS, Schroeder JW, Walsh BW, Simmons LA DNA repair and genome maintenance in Bacillus subtilis. Microbiology and molecular biology reviews : MMBR. 2012 Sep; 76(3):530-64. doi:10.1128/MMBR.05020-11. PMID:22933559
Kaimer C, Graumann PL Players between the worlds: multifunctional DNA translocases. Current opinion in microbiology. 2011 Dec; 14(6):719-25. doi:10.1016/j.mib.2011.10.004. PMID:22047950
Graumann PL, Knust T Dynamics of the bacterial SMC complex and SMC-like proteins involved in DNA repair. Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology. 2009; 17(2):265-75. doi:10.1007/s10577-008-9014-x. PMID:19308706

Original Publications

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